Hiyono Yuizaki ("Hiyo-hiyo") is a character in the anime Spiral: Suiri no Kizuna. She is a second-year student at Tsukiyomi High School and is a journalist for the school newspaper. She is a very chipper intellect and rarely ever seems to be troubled by anything. She has habits of thrusting a pink microphone on unsuspecting people, eavesdropping, and recording every bit of information, rumor, or gossip that comes to her ears. She is also shown to keep a tazer with her, which she will threaten people with (she once almost shocked Kousuke when he threatened to push her out the window).
The seiyuu for Hiyono in the Japanese version is Masumi Asano; in the English version is Caitlin Glass.